Certain phosphorus-containing organic compounds are known to be fire retardant when mixed with or incorporated chemically in polymers. Among such phosphorus-containing compounds are diamino compounds which can, for example, be polymerized with diacyl halides. It is known, for example, to incorporate phosphorus into 2,4-dinitrochlorobenzene by reacting the latter with diethyl phosphite resulting in 2,4-dinitro(diethoxyphosphonyl)benzene. By reducing the nitro groups a diamine is produced. However, the yield of dinitro precursor to the diamino species is low, e.g., about 11%.
Some references of the inventors which describe fire resistant compositions of phosphorus-containing polymers and the monomers thereof include the following:
1. J. A. Mikroyannidis and D. A. Kourtides, "Fire-Resistant Compositions of Epoxy Resins with Phosphorus Compounds", Symposium on Rubber-Modified Thermoset Resins, 186th Annual American Chemical Society Meeting, Washington, D.C., Abstract PMSE 133, Aug. 28-Sept. 2, 1983;
2. J. A. Mikroyannidis and D. A. Kourtides, "Fire-Resistant Epoxy Resins Containing 1-(Di(2-Chloroethoxy phosphinyl)Methyl)-2,4- and 2,6-Diaminobenzene as Curing Agent", Proceedings of the 12th North American Thermal Analysis Society Conference, Williamsburg, VA (Sept. 1983);
3. J. A. Mikroyannidis and D. A. Kourtides, "Curing of Epoxy Resins with 1-[Di(2-Chloroethoxyphosphinyl)Methyl]-2,4- and 2,6-Diaminobenzene", Journal of Applied Polymer Science, Vol. 29, pp. 197-209, (1984);
4. J. A. Mikroyannidis and D. A. Kourtides, "Curing of Epoxy Resins with 1-[Di(2-Chloroethoxyphosphinyl)Methyl]-2,4- and 2,6-Diaminobenzene", National Aeronautics and Space Administration Report No. TM 84350, October 1983;
5. J. A. Mikroyannidis and D. A. Kourtides, "Synthesis and Characterization of Phosphorus-Containing Polyamides and Copolyamides based on 1-[Dialkoxyphosphinyl)Methyl]-2,4- and -2,6-Diaminobenzenes", Journal of Applied Polymer Science, Vol. 29, pp. 941-953 (1984);
6. J. A. Mikroyannidis and D. A. Kourtides, "Synthesis and Characterization of Phosphorus Containing Polyamides and Copolyamides Based on 1-[(Dialkoxyphosphinyl)Methyl]-2,4- and -2,6-Diaminobenzenes", Proceedings of the Society for the Advancement of Materials and Process Engineering, Reno, NV (April 1984); and
7. J. A. Mikroyannidis and D. A. Kourtides, "Curing of Epoxy Resins with 1-[Di(2-Chloroethoxyphosphinyl)Methyl]-2,4- and -2,6-Diaminobenzene", Proceedings of the Society of Plastics Industry Annual Spring Meeting, St. Louis, MO (May 1984).
These references are not considered to be prior art in the present invention.